Electric-wave producer



Oct. 9, 1928. 1,687,220

r S. S. MACKEOWN ELECTRI G WAVE PRODUCER Filed Oct. 16, 1923 23 U LI! )3- l 22 fiy I if hue/70K- 507771181 5. Nacxf'eow/z Patented Oct. 9, 1928.

SAMUEL comm, INCORPORATED, 0! NEW YORK,

S. IACKEOWN, OI ITHAGA, NEW YORK, ASSIGNOB TO WESTERN ELECTRIC.

N. Y., A CORPORATION OF NEW YORK.

nnnc'rnrc-wavn raonucna Application filed October 16, 1988. Serial No. 868,787.

This invention relates to methods and means for producing electric waves.

One object of the invention is to produce electric waves at high efficiency.

Another object of the invention is to operate amplifiers of the variable impedance type at t e highest possible efliciency.

It is known that for the most efiicient production of waves by a variable impedance device in a direct current circuit, for example, by an amplifier of the space current type, it is essential that the space current through the amplifier tube var from a minimum to a maximum value an vice versa in a very sudden or impulsive manner.

It is old to apply sine wave variations of potential to the normally negatively polarized grid in an amplifier in order to impulsively excite the amplifier to obtain amplification of an impressed wave at high efficiency. The highest efliciency obtainable by such a method of operation is limited in any practical case by the fact that the constant negative potential and the sine wave potential applied to the grid of the amplifier become prohibitivel high as the efliciency is increased. Y

In accordance with the present invention, an amplifier is excited by very steep contro impulses transmitted from a relay which converts sine waves into the control impulses.

The rate of change of potential in the control impulses is much greater than in a sine wave of the same amplitude and periodicity and causes the amplifier to operate at a much higher efliciency than is obtainable by sine wave excitation of the amplifier.

Further details regarding the nature, objects and method of operation of the invention are set forth in the following specification with reference to the drawing.

In the drawing. Fig. 1 is a circuit diagram showing one modification of the invention employing transformer couplings between different portions of the circuit each transformer comprising two windings insulated from each other. Figs. 2 and 3 are graphs showing how the impulse excitation takes place. Fig. 4 is a circuit diagram showing an auto-transformer coupling between two vacuum tube devices in tandem and a conductive connection between the last vacuum tube in tandem and the resonant output cir- In Fig. 1, the oscillator 10 of the vacuum tube or other well known type, produces oscillations of low power and of substantially constant frequency in the resonant frequency determining circuit 11. Belay 12 and amphfier 13 in tandem transmit waves from the osclllator 10 to the resonant output circuit 14 tuned by inductance and capacity to the frequency of oscillator 10. Resonant circuit 14 may be the oscillatory radiating circuit of an antenna for transmitting radio waves or maybe any well known form of'energy absorbing work circuit. Relay 12 ma or may not amplify but for convenience o descript1on willbe called an amplifier. Amplifiers 12 and 13 are of the variable impedance type, each being provided with an electron emitt1ng cathode, an electron receiving anode and a gr1d electrode for controlling space current between the anode and cathode.

The condenser 15 and leak resistance 16 cooperate to maintain the grid of amplifier 12 at such a high negative potential with 'respect to the cathode that space current from the source 17 cannot flow except during brief intervals when the positive peaks of waves from source 10'are applied to the grid of amplifier 12. The space current source 17 may be a direct current generator, as shown,

1 or any other well known source of direct current such as a battery or the like. Condenser 18 shunts source 17 to provide a path of low impedance for impulses assing through the output circuit of ampli er 12, and tends to reduce fluctuations in the voltage of source .17. The output circuit of amplifier 12 is inductively coupled to the input circuit of amplifier 13 by means of transformer 19, having primary and secondary windings insulated from each other. Condenser 20 and leak resistance 21 in the input circuit of amplifier 13 cooperate to maintain the grid of the amplifier at such a high negative potential with respect to the cathode that space current from generator or battery 22 cannot flow except during the brief intervals when positive impulses are applied to the grid. Condenser 23, shunting the space current source 22, provides a path of low impedance for impulses passing through the output circuit of the amplifier and tends to reduce fluctuations in the voltage of source 22. The output circuit of amplifier 13 is coupled to resonant circuit 14 by means of transformer 24 having primary and secondary windings insulated from each other.

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condenser 15. It will beseen that this potential is so large that space current is normally reduced to zero. The wave e, impressed from oscillator 10 upon the grid of, amplifier 12 is of sufiicient value to cause space current impulses I to be periodically transmitted through the output circuit of the amplifier.

These impulses, it will be noted, are in syii chronism with the wave e and are produced by positive peaks of wave 6,.

Impulses of space current I in passing through the primary windin of transformer 19 produce waves e Fig. 3, 1n the secondary winding of the transformer in the grid circuit of amplifier 13. The negative polarizing potential 0 across condenser 20 is applied to the grid of amplifier 13 to prevent the trans mission of space current through the amplifier during intervals between the positive peaks of waves e It will be noted that wave e, is much steeper than wave e, impressed upon amplifier 12. The impedance ofamplifier 13 accordingly undergoes very rapid variation from a substantially infinite value to approximately minimum value and vice versa as the control waves e, areapplied to the grid of the tube to periodically cause space current impulses I to be transmitted through the primary windin of transformer 24. These space current impu ses I appearing at re ular intervals synchronously with the positlve peaks of waves 0,, contain a wave component having the same frequency as wave e -and of greatly amplified value. This wave com onent is selected by resonant circuit 14 which functions to provide a relatively high impedance in the output circuit of amplifier 13 for waves of the fre uency of oscillator 10 and of relatively low impedance to waves of higher frequencies. Resistance 25 represents the resistance corresponding to the load and may be the energy dissipating part of an antenna or other work circuit.

Waves of the frequency of oscillator 10 are produced in amplified form at very high efliciency by the operation of amplifiers 12 and 13. The amplified waves of the frequency of oscillator 10 are stored u in resonant circuit 14 whereas waves of higher frequencies in passing throu h the output circuit of amplifier 13 are su jected to very slight impedance and consequently involve very small losses at these high fre uencie s, it bein noted that the impedance 0 amplifier 13 is very small whenever space current passes therethrough.

In Fig. 4, the circuit between vertical lines XX, YY may be substituted between the lines .XX, YY, Fig. 1. Similarl the portion of Fig. 4 between lines YY, tuted between these lines in Fig. 1, and the ortion of Fi 4 to the right of line-ZZ may e substituted to the ri ht of line ZZ,Fig. 1. Inductance coil 30, ig. 4, in the output circuit of amplifier 12, see Fig 1, is provi ed with two variable taps at its remote ends. These taps lead to amplifier tubes 31 arranged in parallel in well known manner. A greater number of amplifiertubes may be connected in parallel between the tubes 31 at the points indicated by the broken lines. Blocking condensers 32 prevent the transmission ofdirect current from the circuits of amplifier 12 to the circuits of amplifier 31 or vice versa and also prevent generator 34, to be described, from being short circuited. High frequency choke coil 33 furnishes a direct current path between the grids and cathodes of amplifier 31. The ids of amplifier 31 are maintained polarized ata high negative otential e see Fig. 3, with respect to the cathodes by means of direct current generator 34 or its equivalent. Resonant circuit 35 corresponding in function to resonant circuit 14, Fig. 1, is conductively connected with its inductance and capacity in parallel between the anodes andcathodes of amplifier 31. The function of generator 34 is similar to that of circuit 15, 16 described in connection with Fig. 1.

In certain tests of the circuit of Fig. 4, substituted in the circuit of Fig. 1, electric waves 7 have been produced at an anode circuit efiiciency for the amplifier 31 of approximately 93%, that is 93% of the direct current energy taken from source 22 was converted into alternating current of the frequency of source 10 and transmitted into oscillatory circuit 35 for radiation or other purposes.

The following data applies to the above mentioned tests Auxiliary amplifier (amplifier 12) Anode voltage (source 17) =400 volts Anode current (1,) milliamperes Inductance in anode circuit (coil 30) =6.5

millihenrys Power amplifier (amplifier 31) Inductance in grid circuit (coil 30) =1.( 5

millihenrys Anode voltage 22) =3615 volts Anode current I,) =525 milliamperes Antenna resistance (resistance 25) =36 ohms Antenna current=7.00 amperes Power input to power amplifier from direct current source 22= 1900 watts Anode circuit efliciency= 93% It will be appreciated that this anode circuit efliciency approaches the theoretical maximum limit of 100% and is, so far as is known, higher than has been obtained by any other known form of high frequency wave producing circuit of the prior art.

may be substi- Power output in antenna (35) =17 60 watts Various modifications of the specific circuits disclosed will be obvious to one skilled in the art without departing from the invention herein disclosed. The features of the invention which are considered novel are set forth in the appended claims.

What is claimed is:

1. The method of amplifying awave which comprises amplifying the peaks of one polarity only of the wave to be amplified and amplifying the peaks of one polarity only of the resulting wave.

2. The method of operating amplifiers-0f the space current type which comprises generating a sine wave, amplifying eaks of one polarity only of said wave to pro uce a source of impulses having a more rapid rate of change from maximum to minimum and vice versa than said sine wave and amplifying peaks of one polarity only of said impulses, whereby said sine wave is reproduced in amplified form at high efliciency.

3. Means for amplifying waves including a plurality of amplifiers of the space current type in tandem, and means associated with each of said amplifiers and normally adjusted to prevent the flow of space current therethrough, whereby waves may be repeated at high efficiency.

4. Means for producing waves at high efiiciency including a plurality of amplifiers of the space current type in tandem, means associated with each said amplifier and nor mally adjusted to prevent the flow of space current therethrough, and a source of waves coupled to the first amplifier in tandem to transmit waves therethrough, whereby amplified waves are produced at high efiiciency in the last amplifier in tandem.

5. Means for producing waves at high efficiency including a source of waves of low power, a plurality of amplifiers of the space current type connected in tandem, means associated with said amplifiers and normally adjusted to prevent the flow of space current therethrough, an output circuit for the last amplifier in tandem tuned to the frequency of waves from said source, means for coupling said source to the first amplifier in tandem, whereby high power waves of the frequency of waves from said source are reproduced at high efiiciency in said tuned output circuit.

6. Means for producing waves at high efiiciency including a plurality of relays of the ariable impedance type in tandem, means adusted to render said relays normally substantially infinite in impedance, 8. source of waves of low power, means to couple said source to the first relay in tandem, whereby the impedance of said relays is periodically varied from substantially infinite to a minimum value and vice versa in synchronism with waves from said source, and an output circuit for the last relay in tandem tuned to the frequency of waves from said source.

7. Means for producing waves at high efficiency including a plurality of relays of the variable impedance type in tandem, means rendering said relays normally substantially infinite in impedance, 0. source o waves of low power, means to couple said source to the first relay in tandem whereby the impedance of said relays is periodically varied from substantially infinite to a minimum value and vice versa in synchronism with waves from said source, and a resonant circuit tuned to the frequency of waves from said source conductively connected to the output of the last relay in tandem.

8. Means for producing waves at high efiiciency including a lurality of amplifiers of the variable impe ance type in tandem, an output circuit for the last amplifier in tandem tuned to the frequency of waves to be produced, means adjusted to render said amplifiers normally substantially infinite in impedance, and means for impressing energy upon the first amplifier in tandem to cause said amplifiers to periodically and impulsively vary from substantially infinite to minimum impedance and vice versa at the same frequency as the waves to be roduced, whereby high power waves of said equency are produced at high efficiency in said tuned output circuit.

9. Means for producing waves at high efficiency including a plurality of amplifiers of the space current type connected in tandem, means comprising a. grid leak resistance and a condenser in shunt thereto associated with said amplifiers and adjusted to normally prevent the flow of space current therethrough, inductive couplings between said amplifiers, a source of waves of low power coupled to said first amplifier in tandem, and a resonant circuit in the output of the last amplifier in tandem, said circuit being tuned to the frequency of waves from said source, whereby amplified waves of said frequenc are reproduced in said resonant circuit at big efficiency.

10. Means for producing waves at high efliciency, including a source of waves of low power, an auxiliary amplifier of the variable impedance type having an input and an output circuit, means associated with said input circuit adjusted to render said amplifier substantially infinite in impedance and to allow the positive peaks only of waves from said source to render said amplifier substantially minimum in impedance, a power amplifier having an input circuit coupled to the output circuit of said auxiliary amplifier, said input circuit including means for rendering the power amplifier normally substantially infinite in impedance and allowing the positive peaks of waves impressed upon the input circuit of said amplifier to periodically render said amplifier substantially minimum in impedance, an output circuit for said power am- 4: y 1450mm) plifier of high impedanoe to waves of the freonl quency of said source and of low impedance pea to waves of higher frequency, whereby .waves of the other polarity.

of the frequency of said source are repro- In witnesswhereof, I hereunto eubscribe v 5 duced in said out ut circuit at'high eflicieney. my name this 26th day of- September-A.- D., 11. The metho which-comprises repeating 1928. the peaks of one polarity only of a wave to be repeated, repeating the peaks of one polarity S. S. MACKEOWN.

' {80f thetresulting wav ma utilizing the so repeated to the exe ueionlot the peaks 

